and similar in. many respects but different in others, afe in
reality so many distinct species-or merely varieties ofOn'é
species. The doubt can only be» removed by a comprehensive
survey of the phenomena related to the origin of varied
ties in breeds, and of facts in the animal economy; connected
with their propagation. The inquiry divides itself into two
heads; the first is an investigation of 'phenomena taking
place in the particular races to be compared, and in respect
to which the question has been set on foot ; the sêCöhd refers
to other tribes bearing some analogy in their Structure, and
in the general laws. of . their economy to these particular
races. The most immediate and decisive proof that the diversities
observed between any-given tribes, constitute only
varieties, arises from the discovery of corresponding" pié-
nomena of variation in those veryPacês which arethér subjects
of comparison. Thus, i f any one should maintain that
asses are degenerated horses, he Would establish his opinion
to the conviction of every one, if he Could only point out an
instance in which horses have actually fhfgenerated into
asses. A less direct though still sufficient evidence may^bd
furnished by facts which bear, by analogy, oh the su b je c tif
research. I f it can be proved that certaih deriatiOris fn thé
form and structure of individuals, analogous to those which
are the subjects- of inquiry, actually occur in other tribes;
that a provision is made for their developëüteht Jh the
of the animal economy, that there is nothing in the change'
supposed to have taken place out of the usual cöürse^óf
organized nature, the inference that such deviations constitute
merely varieties, and do not amount to spécifie distinctions,
will be established with a considerable degree of probability,
though scarcely with that decisive evidence which
the direct manner of proof affords. In adverting to researches
into the physical varieties of mankind, the former
method oPinquiry must be termed the historical or ethnographical
one!, and the latter the analogical. The first comprises
a survey of the different races of men, an investigation
of their physical history, the ethnography, as it is termed,
of every tribe of the human family, undertaken and pursued
in such a manner as to enable us to determine what changes
have' actually arisen in the physical characters of nations or
human races. The. second involves every consideration
founded on physiolOgypor the laws of the animal economy,
that may serve, to elu cid ate the relation of different tribes to
each other in respect to their physical characters and constitution.
It will b e e n d e a v o u r in the course of this work
to go through both of these investigations, and -lay before
my readers -their results; b u t-1 shall take up-these two departments
of inquiry in a different order from that in which
I have mentioned them. Several motives - have determined
me to pursue this plan, but principally the impression that
my readers will-proceed with greater facility and-advantage
to the ethnographical researches, which form the greater part
of my work, after they have directed their attention to the
physiological and anatomical facts to be comprised: in the
other'part. -
<3^^Analogical Investigation o f the ISfature o f
Varieties—Different Heads o f this Inquiry enumerated.
This part of our inquiry ought to comprise a smrvey of the
whole theory of varieties arising in the breed of progeny of
organized beings, and an investigation of the nature of such
deviations from the structure of the race, as well as of the
circumstances by which their extent is limited or confined
within certain bounds. It includes the attempt to determine
what in the structure of species is permanent, and what is
liable to transmutation, a question bordering closely on subjects
of controversy, which have been much discussed among
naturalists of the present day. By confining myself'strictly
to the examination of facts, and avoiding whatever is conjectural
and imaginary, I shall spare myself the necessityof
entering on disputed ground. The question to which I have
to direct the attention of my readers is, what are the characters
of organization which are permanently transmitted in
the species of animals and of plants, without change or
variety, and what are those which are liable to deviation ?-
It seems to be a fact, that fhe most permanent and iqivari